Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Activity

A summary of stock option activity for the three months ended March 31, 2022 is as follows:

	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term in Years
Outstanding at December 31, 2021		2,413,194		$	7.04		9.06
Granted		1,155,570		$	2.35
Cancelled/forfeited/expired		(365,250	)	$	6.44
Outstanding at March 31, 2022		3,203,514		$	5.50		7.80
Vested and unvested expected to vest, March 31, 2022		3,162,485		$	5.52		7.78

Assumptions Used for Determining Fair Value of Stock Options Under Black-Scholes Pricing Model

The assumptions used in the Black-Scholes pricing model for stock options granted during the three months ended March 31, 2022 were as follows:

	2022
Stock and exercise prices	$2.32 - $2.39
Expected dividend yield	0.00%
Discount rate-bond equivalent yield	1.76% - 2.41%
Expected life (in years)	5.55 - 6.03
Expected volatility	161% - 163%

Effects of Stock-Based Compensation Related to Equity Awards to Employees and Nonemployees on Condensed Statement of Operations and Comprehensive Loss

The following table presents the effects of stock-based compensation related to equity awards to employees and nonemployees on the unaudited condensed statements of operations and comprehensive loss during the periods presented:

	For the Three Months Ended March 31,
	2021		2022
Stock Options
Cost of revenues	$	94	$	208
Research and development expenses		44		166
General and administrative expenses		260		1,802
Sales and marketing expenses		62		141
Total expenses related to stock options		460		2,317